液化条件下多孔介质中CO2水合物的生成特性

基于水合物法的二氧化碳气体地层封存和固化技术是实现温室气体减排的有效方法之一。进行液化条件下多孔介质水合物的生成过程及其生成特性研究,有助于进一步丰富不同相态CO2的地层存储规律。为此,利用气体水合物生成与分解模拟实验装置研究了粒径分别为24目、32目、40目和60目四种不同的石英砂体系中多孔介质水合物的生 成过程,实验温度选定276.5 K,初始压力为4.85 MPa。结果表明：在液化条件下,水合物生成的诱导时间随多孔介质粒径的减小而缩短,并且当粒径减小到40目附近时,诱导时间将急剧减小,与32目的石英砂体系相比,此时诱导时间明显缩短超过2/3；多孔介质对水合物生成速率和储气量的影响较为显著且存在一临界粒径尺寸,在40目的石英砂介质中,液化条件下水合物的最大生成速率和储气量分别达到了12.35×10-4 mol/h 和30.599 L/L。

Formation characteristics of carbon dioxide hydrate in porous media under liquefaction condition

Stratigraphic sequestration based on hydrate technology is considered to be an effective way to achieve the solidification and storage of CO2 gas. It is important to investigate the influence of different particle sizes on the formation characteristics of carbon dioxide hydrate under liquefaction condition and further enrich the formation storage laws of CO2 in different phases. To this end, the experiments for CO2 hydrate formation were carried out in porous media of 24, 32, 40 and 60 meshes using the formation and decomposition experiment system for gas hydrate. The experimental temperature was fixed at 276.5 K and the initial pressure is 4.85 MPa. The results showed that, under liquefaction conditions, the induction time of hydrate formation decreases with the decrease of the particle size of the porous medium, and when the particle size is reduced to around 40 mesh, the induction time will decrease sharply, compared with the 32 mesh quartz sand system in comparison, the induction time is significantly shortened by more than 2/3 at this time; the influence of porous media on the rate of hydrate formation and gas storage is more significant, and there is a critical particle size. In 40 mesh quartz sand medium, the maximum formation rate of hydrate and gas storage capacity under liquefaction conditions reached 12.35×10-4 mol/h and 30.599 L/L, respectively.